The present invention relates generally to milling machines and more particularly to an improvement to cold milling machines design for cutting asphalt, concrete and other road surface materials. My improvement to such machines causes them to make cuts that are intermittent and spaced, enabling them to form "rumble strips" along the shoulders of highways.
It will be appreciated by those skilled in the art that cold milling machines have existed for many years. Such machines have specially designed milling drums with righted sections protruding in a spiral pattern radially outwardly from the drum. Cutting tool holders are mounted generally on the righted section and cutting tools are fitted within the cutting tool holders. These machines are designed to travel along a road, highway or other thoroughfare and make a continuous cut (up to 6 feet in width and 12 inches in depth) of the pavement over which they pass. Machines of this type generally fall in the category of road building or material handling equipment.
Known cold milling machines cut the top layer of the road surface material, chop the material into granular form, and rake the material onto a conveyor so that it can be removed from the site. The road can then be paved with new material, keeping the road surface at the desired height and weight.
My invention is directed to a modification of known cold milling machines which will enable the machines to cut, in the shoulders of existing highways, a safety feature known generally as "rumble" strips and to perform this task at increased efficiency and reduced costs.
Rumble strips are a variation of features used to control speed in private parking lots and the like referred to as "speed bumps". The precursor to rumble strips was the use of fluted ridges, creating a washboard effect, on highways and traffic passageways, particularly during the construction phase of the nationwide interstate highway system in this country. Because the interstate highways were built in sections, it was frequently required for travelers to exit the section of completed highway onto local roads and travel local roads for a period of time until reaching the next section of completed interstate highway. Motorists would often fail to recognize the termination point of a complete section of an interstate highway because of the uniform appearance of the newly constructed interstate highway system, and because travelling motorists were not familiar with the interstate highway system. Missing the required exit often would result in accidents because of the high speed of travel over unfinished interstate sections.
In order to alert motorists to the fact that they were approaching a required exit, a series of fluted ridges were placed across the highway, spanning the highway and running perpendicular to the direction of traffic flow. When an automobile travelling at a high rate of speed passed over the fluted ridges, the tires would create a roaring sound, startling the driver and causing him to be more alert to his surroundings. By startling the driver and causing him to become more alert, he would notice the signage that provided instructions regarding exiting the segment of completed interstate highway, thus preventing accidents as a result of missed exits and crashes at a high rate of speed into an unfinished portion of the interstate.